JAAOS2018 Flashcards
Radiation dose relationship to proximity?
<div>radiation exposure DECREASES proportional to square of distance from source to surgeon (ie, small increases in distance = exponential decreases in radiation exposure)</div>
Types of radiation exposure effects?
Effects of Radiation<div><div>Exposure Deterministic</div><div>Effects Health consequences that occur after certain threshold of photons absorbed (eg, cataracts, hair loss, infertility)</div><div><br></br></div><div>Stochastic effects</div><div>Health consequences that occur randomly (each additional photon absorbed increases risk, but no threshold exists.) Mostly applied to health consequences as a result of DNA damage Eg, Cancer<br></br></div></div>
Most susceptible tissue to cancer induction from radiation? (higher number more sensitive)
“<img></img>”
Yearly radiation dose limit?
<div>20mSv/ year (ICRP), or 50mSv/year (NCRP). ICRP is international, and is the lower limit, so safer to use this one</div>
<div>1 Sv of cumulative radiation exposure =</div>
1 Sv of cumulative radiation exposure =<div>60% increase in risk of developing solid cancer</div><div>5% increase absolute risk of mortality from cancer</div><div>so, if exposure limit set at 20mSv/year, 50 years required before one is exposed to 1Sv, and getting the above mentioned risks</div><div><br></br></div><div>Cataract risk = same threshold risk for 20mSv/year</div><div><br></br></div><div>Offspring risk</div><div>Highest risk during 1st trimester (organogenesis)</div><div><br></br></div><div>Stochastic effect of increased fetal cancer risk RR of 1.4 for every 10mGy …but absolute risk of childhood cancer after 10mGy = 0.3%, and baseline absolute risk = 0.2%</div><div><br></br></div><div>ICRP still recommends prenatal radiation exposure limit of 0.5mSv/mo during pregnancy<br></br></div>
Methods to decrease radiation exposure?
Lead apron 0.25-.5mm thick (blocks 90-95%)<div>Leaded glasses (reduces 90%) - eliminates risk of cataracts</div><div>C-position - stand on intensifier side (4-8x less)</div><div>- 1 m away (only get -.3% of dose)</div><div>- Other staff > 2m away<br></br><div><br></br></div></div>
Effects of Vit D on Skeletal Muscle?
- Enhanced myosin on actin -> more forceful contraction<div>2. Stronger UE/LE indices</div><div>3. Increased vertical ump</div><div>4. Lower incidence of stress fracture</div><div><br></br></div><div>JAAOS - Effects of Vitamin D on Skeletal Muscle and Athletic Performance</div><div><br></br></div>
Felix classification of periprostehtic tibial stress fractures?
“Based on location and I-IV and stability A/B, C = intrap<div><br></br></div><div><img></img><br></br></div>”
Indications for ALL reconstruction?
- young<div>- active</div><div>- pathologic rotatory laxity and imaging suggesting ALL injury</div><div>- Revision ACL wthout other factors causing failure</div>
Factors to optimize fracture healing?
“<div> <div> <div><img></img></div> </div></div>”
4 known muscle/bone factors implicated in supporting inflammatory phase of bone healing?
ILGF-1<div>Myostatin</div><div>BMPs (1)</div><div>Osteonectin</div>
Inflammatory cascade of # hematoma?
Migration of PMN (hours)<div>Macrophages replace neutrophils</div><div>T lymphoctytes initiate adaptive immune response</div><div>Mast cells help in bone repair<br></br></div>
RF for poor bone heaing in DM?
- peripheral neuropathy<div>- Operative time inc 15% risk for every 10 mins (past a set time..)</div><div>- HbA1C > 7</div>
Patient related risk factors for poor bone healing?
- DM 1 and 2<div>- NSAIDs</div><div>- Recent MVC</div>
RF for distal femur non-union
- obesity<div>- open</div><div>- infection</div><div>- stainless steel plate</div><div>(note - smoking, DM, steroids not on there)</div>
RF for revision surgery in tibial non-union?
- open<div>- transverse</div><div>- # gap</div><div>(No smoking/DM or steroids)</div>
Contraindication to VAC?
CSF leak<div>Bleeding disrder</div><div>Allergic to dressing</div>
Mechanism of VAC?
Speeds up 2nd intent<div>Increase blood flow</div><div>Removes edema and exudate</div>
RF for high risk SS complications (i.e. Consider a VAC)
DM, ASA >3, obesity smoker, hypoalbumin, steroids, high tension, revision
Contraindications to DFVO?
Absolute<div>Extreme valgus with tibial subluxation</div><div>Gross knee instability</div><div>Tricompartmental OA</div><div><br></br></div><div>Note: medial OA is absolute contra-indication, whereas moderate PF OA can be addressed with VDRO (although severe PF OA should be tx with arthroplasty) (medial OA)</div><div>Flexion contracture >15 deg</div><div><br></br></div><div>Relative Patient:</div><div>high BMI, RA, age>65 Knee: severe PF OA, severe lat comp bone loss, hx of SA<br></br></div>
Transfibular approach in TAA?JAAOS
Preserves deltoid ligament. Sacrificed ant talofibular… keeps skin blood supply, less bone loss
1st time dislocator OA?
> 50% develop some evidence of OA regardless of treatment.<div>ALso directly related to #d/l, cartilaginous trauma and timing or stabilization</div>
MPFL Origin and Insertion?
DA to Add tubercle (distal anterior)<div>Prox 1/2 of patella and quads tendon</div><div>Isometric</div>
Pathognomonic findings of patellar instability?
“Spur, double contour, crossing sign<div>Must have true lateral.</div><div><div> <div> <div><img></img></div> </div></div></div>”
Indications for trochleoplasty?
Dejour B/D, Spur > 5mm<div>Still need TTO and MPFL.</div><div>Contra - PF OA, open physis</div>
TTO Indications?
TTTG> 2 cm on CT, increased TT-PCL, Alta >1.2 CDS<div>Relative- lateral PF lesion</div><div>Coal is TTTG 10 mm</div>
Dejour Classification?
“<img></img>”
How much bone graft from RIA?
25-90 cc
How long till RIA regenerates?
14 months can reharvest.
Schottle point?
“True lateral<div>Posterior femoral cortex line, perpendicular lines at the start of the posterior curve and then most posterior point of bluemensaat. Go in this and anterior to blue.</div><div><img></img><br></br></div>”
Most common site of megaporthesis failure?
Proximal tibia
Main issues with megaprosthesis?
Infection<div>Soft tissue attachments</div>
Causes of GH chondral defects?
instability, iatrogenic chondrolysis, focal AVN, septic arthritis, RCTs, OCD
Iatrogenic causes of GH chondral defects?
local infusion<div>non-absorbale sutures</div><div>thermal devices</div><div>direct trauma</div><div>rate is 13%</div>
Ratcliff focal AVN of femoral head?
“1. XR sclerosis and Collapse<div>2. Neck AVN from fracture to the physis</div><div>3. Focla sclerosis of superolateral head</div><div><br></br></div><div><br></br></div><div><img></img><br></br></div>”
Acceptable reduction in peds femoral neck fractures?
Reduces non/malunion<div>Delbet</div><div>2 - <5 deg and < 2 mm trans</div><div>3 - < 10 deg</div>
Operative indications for tibial plateau?
<div> <div> <div> <div>Relative indications for surgery are an articular step-off of .3 mm, condylar widening of .5 mm, and 5 deg of coronal alignment disruption</div> </div> </div></div>
RF for non-union in tib plateau fractures?
Schatker 5, comminution, unstable fixtion, failure of implant
Prevention of UCL injuries?
“no pitching at least 4/12, limit counts and have rest days, single team/no overlapping seasons, don’t play pitcher anc catcher, play other sports, stop when it hurts.”
Reasons for poor sacral fixation?
cancellous bone, short capacious S1 pedicles, increase sacral slope = inc shear, fixation is anterior to the L5-S1 pivot point
Indications for spinopelvic fixation?
long contruct, high grade spondy, unstable sacral #, neuromuscular kid with deforming/obliquity
Triangular osteosynthesis?
“Skips sacrum - fixation from lumbar pedicle to the ilium. For vertical shear sacral fracture when you can’t get good Sacral fixation.”
MSTS Staging - most relevant for bone sarcoma
grade, site (intra/extracompartmental), mets
AJCC staging? Based on evidence
size (8 cm), grade (differentiation), LN, Mets.
STS where you want CT C/A/P?
Myxoid liposarcoma, epitheliod, leiomyosarcoma, angiosarcoma (LAME)
RF for VTE in c-spine sugery?
Posterior<div>Male</div><div>Teaching hopsital</div><div>Pulmonary or circulatory disease</div><div>Electrolyte abn</div>
RF for VTE in elective spine OR?
Corpectomy, BMI>40, paraplegia, ASA>4, LOs>7, SCI, medical comorbid
“Pathology of hip instability in Down’s?”
delayed walking, hypotonia, laxity
“Bony deformity in Down’s hip?”
Coxa valga, anteversion, acetabular dysplasia, acetabular retroversion (posterior uncoverage. UNSTABLE in flexion, adduction and internal
“Treatment of hip instability in Down’s?”
VDRO if <7<div>Pelvic osteotomy adolescents</div><div>- PAO or triple for posterior coverage preferrred.</div>
Female athletic triad?
New def - low energy, mentrual dysfunction, low BMD
Relative energy deficiency in sports: (can apply to males too)
impaired bone health and energy from malnutrition and endocrine abnormalities. INcreased risk for stress fractures.
ACL risk factors in female? (not necessarily causal)
narrow notch, increased tibial slope, est on laxity, landing mechanics
Concussions worse in whic sex?
Females - higher incidence and severity and deficits.
In dual mobility, which articulation move first?
Larger articulation only moves when smaller one maxes out and impinges between neck and insert.
Definition of jumping distance?
<div> <div> <div> <div>the degree of lateral translation of the center of the fem- oral head that is needed for disloca- tion to occur</div> </div> </div></div>
Retentive failure?
Loss of retaining power of poly liner rim holding small head in place. Only seen in dual mobility.
RF for concussion?
previous concussion, high risk sport, female, 9-22 yrs, contact positions, loss of conciousness
4 categories of concussive syptoms?
somatic, cognitive, emotional, sleep
CTE symptoms:
behavioral, impulsivity, depression
Season and Career ending injuries in concussion:
Season: > 2, dec academic/atheltic performance, abnormal MRI/CT<div>Career: decreasing energy of injury, ICH, prolonged post concussive symptoms, MR abnormalities (Chiari)</div>
Concussion RTP protocol:
“<div> <div> <div><img></img></div> </div></div>”
Maddocks questions?
At what venue are we today?<br></br>Which half is it now?<br></br>Who scored last in this match?<br></br>What did you play last week?<br></br>Did your team win the last game?
Laterla extrusion in perthes?
epiphyseal width to amount of head extruded, >20 poor prognosis
Characteristic deformity in basal thumb arthritis?
adducted with MCP hyperextension.
Roberts view for basal thumb arthritis
“hyperpronation.<div><img></img><br></br></div>”
Requirements for a biceps to triceps transfer for elbow extension?
Intact brachialis and supinator
Definition of tetraplegia?
Cervical level SCI
ICSHT
internationl classification for surgery of the hand in tetraplegia<div>- defines working uscles below the elbow starting at BR and going distal.</div>
How to determine if both ECRB and ECRL are working?
5/5 power<div>Groove between muscle bellies - bean sign</div><div>ECRL only - radial deviates (2nd MC), 4/5 power</div>
Candidats for TT in tetraplegia?
Functional goals, motivated, understands benefits and limitations, emotionally stable, adjusted to disability, commit to rehab.<div>C5-8 level injury, ICSHT 1 or better (need at least BR)</div>
Candidate for functional electrical stimulation?
C5-6 level<div>No hand/wrist function with no surgical options</div><div>Can be driven by voice, resp, other movement. Best combined with TT.</div>
3D PSI for hip arthroplasty?
- better accuracy for cup<div>- no difference in duration of OR</div><div>- More expensive</div><div>- same complications</div><div>- outcomes TBD</div>
Principles of early pilon fixation?
~12 hrs<div>- better reduction, similar fucntional outcome</div><div>- exclude in - hemmoragic blisters, contaminated, never between 3-5 days, EtOH, schizo, DM</div><div>- done by traumatologist</div>
Angiosomes of the ankle?
- Anterior tibial<div>2. Posterior tibial</div><div>3. Peroneal</div>
Techniques to reduce soft tissue issues in pilon #?
- early OR<div>- Staged OR</div><div>- upgrading</div><div>- Partial fixation/sequential</div><div>- Fusion</div><div>- shortening</div><div>- transyndesmotic fixation</div><div>- MIS plating</div><div>- ring fixator</div>
Factors associated with instability in RTSA
- subscap def<div>- BMI >30</div><div>- Males</div><div>- revision</div><div>- deltopec approach</div><div>- bone loss</div><div>- trauma RTSA</div><div>- acromial #</div><div>- infection</div>
Lateralized RTSA
- increased stability<div>- tensions deltoid</div><div>- acromial stress #</div><div>- ?early glenoid failure</div><div><br></br></div>
MIS vs. Open SI fusion?
- less blood loss<div>- dec LOS</div><div>- dec OR time</div><div>- less post op pain</div><div>- complications same</div><div>- outcomes similar</div>
Implicated factors in rapid post arhtroscopic chondrolysis?
- indolent infection<div>- mechanical damage</div><div>- anchors?</div><div>- thermal injury</div><div>- chemical injury - local pump</div>
How many bugs does it take to cause SSI with implant present?
10, 1000-100000 without.
Typical deformity in distal femur fracture?<div>Spot for blocking screws?</div><div>Sept 2018</div>
Extension and valgus (occasionally varus)<div>Anterior and Lateral</div>
Proximal tibia fracture deformity?<div>Blocking screw locations?</div><div>Sept 2018</div>
Valgus, procurvatum.<div>Blocking screws posterior and lateral</div>
Judging proper AP for start point in tibial nail?
“Lateral plateau should bisect middle of proximal fibula<div><img></img><br></br></div><div><br></br></div>”
Rate of PF damage in suprapatellar nailing?
30% in repeat scope.
Safe zome for tibial nail start point?
“9 mm lateral to midline, 3 mm lateral to TT<div><img></img><br></br></div>”
“Treatment for patellar instability you CAN’T do in open physis?”
TTO, Trochleoplasty
Indications for lateral release in patellar instability?
TTTG>20<div>Lateral tilt</div><div>Fixed dislocations</div>
Options for MPFL reconstruction in skelettaly immature?
MPFL - R<div>Guided growth</div><div>Hamstring sling (around MCL or Adductor magnus)</div><div>Patellar tendon slip</div><div>Realingment</div><div>- Roux Goldwaith</div><div>- Nietosvaara - semi-T out and aorund into schottle</div>
What are the 3 kinematic axis of the normal knee?
Flexion axis of tibia<div>Flexion axis of patella</div><div>Longitudinal rotational axis - IR/ER</div>
Distance from ACJ of CC ligaments?
Trapezoid - 2.5 cm<div>Conoid - 3.5 cm (20% length of clavicle)</div>
RF for recurrence of lateral ankle instability?
- global laxity<div>- high demand</div><div>- hindfoot cavovarus</div><div>- non-anatomic recon</div>
Most common nerve injured in scopic lateral lig repair of the ankle?<div>Safe zone?</div>
Communicating branch of sural and SPN - 4.7 cm lat to lat mal (safe zone 1.5 cm)
Start point for perc pedicle screw?<div>Wire?</div><div>Trajectory?</div>
- center of lat pedicle on PA<div>- stay in lat 2/3 (dec medial wall penetration)</div><div>- just enter body on lat</div><div>- then use guide wire<br></br><div><br></br></div></div>
Blocks to rod placement in PPSI?
- muscle fascia<div>- bone (TP in T spine)</div><div>- uneven screw head alignment</div><div>- poor rod contour</div><div>- adjacent facet</div><div>- TL junction change in kyphosis</div>
Reduction phases in rod insertion during spine surgery?
- indirect, pt position<div>- manipulation of endplate</div><div>- distraction through rod</div>
Factors affecting local inflammation?
- soft tissue injury<div>- fracture hematoma</div><div>- stability</div><div><br></br></div>
Systemic factors affecting inflammation?
Acute disease - polytrauma, sepsis<div>Chronic disease</div><div>Drugs - anti-inflam</div>
4 muscle bone factors implicated in inflammatory phase of fracture healing?
- ILGF - 1, early myokine<div>- myostatin</div><div>- BMPs</div><div>- Osteonectin</div><div><br></br></div>
Risk factors for bone healing in DM?
- neuropathy,<div>- length of OR, additional 10 mins risk 15% healing…</div><div>HbA1C> 7</div>
RF for non-union of DFF?
obesity<div>open</div><div>infection</div><div>stainless steel plate</div>
RF for revision in tibial non-union
- open<div>- transverse</div><div>- fracture gap</div>
Shoulder hyperlaxity? Anterior and Inferior?
> 85 deg ER in add<div>> 105 deg hyper abduct</div>
Pathology associated with GH chondral defects?
instability, iatrogenic chondrolysis, focal ON, septic arthritis, RCT
ASMI pitching guidelines?
- 4/12 no pitching!<div>- pitch counts and rest days</div><div>- single team</div><div>- no pitcher catcher combos</div><div>- play other sports</div><div>- rest when pain</div>
MSTS staging for bone sarcoma?
“<div> <div> <div><img></img></div> </div></div>”
AJCC for bone sarcoma?
“<div> <div> <div><img></img></div> </div></div>”
AJCC for STS?
“<div> <div> <div><img></img></div> </div></div>”
RF for VTE in spine surgery?
Risk factors for VTE:<div>Posterior fusion (highest risk)</div><div>Male</div><div>Teaching hospital</div><div>Pulmonary/circulation pathology</div><div>Electrolyte abnormalities<br></br></div><div>Corpectomy</div><div>obesity</div><div>>ASA</div><div>> LOS</div><div>Paraplegia</div>
Contributors to hip instability in DS?
<div>Soft tissue</div>
- lig laxity<div>- capsula insufficiency</div><div>- hypotonia</div><div>Boney</div><div>- coxa valga</div><div>- anteversion neck</div><div>- dysplasia</div><div>- retroversion cup</div>
Location of CAM? Position of impingement?
Anterosuperior neck, FADIR
Best XR view for CAM?
“Modified Dunn<div><img></img><br></br></div>”
Definition of CAM/overcoverage?
CEA or LCEA of >40
Hip injection anterior?
2-3 cm below asis and 3 cm lateral to femoral artery
Complications of joint aspiration and injection
“<img></img>”
Age related changes in the ACL?
“<img></img>”
Normal 4-5 IMA, 5th MTP angle?
IMA - 6.5<div>MTPA <13</div>
Factors affecting loosening in medial UKA?
-metal backed > mobile<div>- 2 > 1 peg</div><div>- malalignment</div><div>- lowering med joint > 2mm relative to lat</div><div>- poor femoral fixation</div><div>- varus inclination tibia > 4 deg</div><div>- anteriorly angled fem cut</div><div><br></br></div>
Most important preditor of lateral compartment progression in med UKA?
- lat OA grade at time of UKA
Benefits of hemi?
- less OR time<div>- less blood loss</div><div>- more stable</div><div>- fewer post op comlications</div>
Benefits of THA in fracture?
- better pain relief<div>- lower long term re-op</div><div><br></br></div>
1 year mortality in hip fracture?<div>Directly related to?</div>
30-40%, related to time to OR. <48 hrs dec mortality but even 24 –> 12 is better for 30 day mortality
Amount of abx in 40g bag of cement? (definitive fixation)
> 4.5g decreases strength<div><2g/40g is standard</div><div>In staged revision 3.4 - 8.6 g, 8 grams changes workability</div>
CAM - complete arthroscopic management indications for GH OA?
- <50<div>- active</div><div>- symptomatic OA</div><div>- retained joint space</div>
Contraindications to CAM for GHOA?
“<img></img>”
Compesnatory plantar flexors?
PL, PB, FHL, FDL (these 4 may mask injury by being intact.<div>TP</div>
Advantages of FHL TT in achilles over PB/FDL?
- stronger<div>- same line of pull</div><div>- in-phase</div><div>- close to achilles</div><div>- brings in vascularity</div>
Rate of contralateral fem neck/shaft fracture?
9%
Indications for biopsy in lipomatous mass?
Heterogenous signal intensity<div>Lack isointense signal compared to fat</div><div>Post-contrast enhancement with Gad Necrotic areas<br></br></div>
MRI findings of ATL?
+ Deep to Fascia<div>+ Larger than lipoma >10 cm</div><div>+ Thicker fibrous septae >2 mm</div><div>+ Post-Contrast Gad enhancement<br></br></div>
4 ossification centers in os acromiale?
A –> P<div>pre, meso, meta, basi</div>
